#include <stdio.h>
#include <string.h>


int my_strlen(const char* input)
{
	int ret = 0;
	while (*input)// 1  2   \0
	{
		input++;
		ret++;
	}
	return ret;
}


int main()
{
	char arr[] = "abc";
	printf("%d", my_strlen(arr));
	return 0;
}